End-thrust apparatus for fluid-pressure turbines.



F. HODGKINSON.

END TEEUST APPARATUS EOE FLUID PRESSURE TURBINES.

APPLICATION FILED JAN. 20, 1904. RENEWED SEPT. 14, 1907.` 95395306,Patented Mar, 29, 1910.

NVENTOR.

4 SHEETS-SHEET 1.

WITNESSES P. HODGKINSON.

END THRUST APPARATUS POR FLUID PRESSURE TURBINES. APPLIOATIO FILED JAN.2o, 1904. RENEWED SEPT. 14, 1907.

953,539. Patented. 01012201910;

4 SHEETS-SHEET 2.

W/TNESSES:

F. HODGKINSON.

END THRUST APPARATUS FOR FLUIDPRESSURE TURBINES.

APPLICATION FILED JAN. 20, 1904. RENEWBD SEPT. 14, 1907.

Patented Mar.29, 1910.

4 SHEETS-SHEBT 3.

P. HODGKINSON.

END TERUST APPARATUS FOR FLUID PRESSURE TURBINES.

APPLIOATION FILED 11111.20, 1904. Bmmwnn SEPT. 14, 1907.

4 SHEETS-SHEET 953953@ Patented 111111.29, 1910.

Ely

SmAAflil WITNESS/SS.'

@LA LLvv Jj TTE STATE@ PATENT FTQT.

FRANCIS HODGKINSON, OF EDGEVVOOD PARK, PENNSYLVANIA, ASSIGNOR- TO THEWEST- INGHOUSE4 MACHINE COMPANY, A CORPORATON OF PENNSYLVANIA.

END-THRUST APPARATUS FR FLUID-PRESSURE TURBINES.

Specification of Letters Patent.

Patented Mar. 29, 1910.

Application filed January 20, 1904, Serial No. 189,897. RenewedSeptember 14, 1907. Serial No. 392,822.

y[o all whom et may concern:

. Vania, United States of America, have invented a new aud usefulImprovement in End-Thrust Apparatus for Fluid-Pressure Turbines, ofwhich the following is a specification.

' My invention relates to fluid-pressure turbines, and particularly tosuch as operate against considerable pressures exerted as endthrustsupon their shafts, and it has for its object to provide means forcounter-balancing such end thrusts in a simple and effective manner andto such a degree as to promote satisfactory operation of the engine as awhole.

Figure l is a llongitudinal sectional view -ofa reversing turbineconstructed in accordance with my invention. Fig. 2 is a view, partiallyin side elevation and partially in section,.0t` a portion of one of theturbines shown in F ig. l.' Fig. 3 is a sectional, detail view of amodification of one of the parts of the end thrust counter-balancingmechair, ism.` Fig. 4 is a view, partially in elevation and partially insection, of a vertical turbine equipped with my invention. Fig.l 5 is avertical, sectional view of a modified form or" my invention as adaptedto a vertical turbine.

In the operation of horizont-al steam turbines for driving electricgenerators and for similar purposes, it is obvious that there is nomaterial end thrust upon the turbine shafts except in cases where theturbines are of the single-flow type; that is, in which the steam isintroduced at one end and exhausted at the other, and in such cases, ithas been usual to provide a piston to balance the end thrust produced bythe pressure of the steam against the rotating drum of the turbine. Inthe use of turbines for driving the propelurs of marine vessels,however, it is obvious that the end thrust due to the propeller actionis considerable and that some means should be provided tocounter-balance it. The end pressure thus exerted may, of

course, be taken by an ordinary form o't thrust bearing, such as iscommonly ein! ployed in marine practice, but such bearings are subjectto considerable wear and large t'rictional losses. lt therefore proposeto provide a means which will automatically balance the end thrustcaused by the propellers throughout all the limits ot regular operation.

As here shown, the turbine l is of the multi-cellular or Parsons type,in which the main rotating member orv drum 2 is provided with a seriesof annular sets of blades or buckets 3 and the casing 4L is providedwith a Vcorresponding series of annular sets of guide-vanes 5, whichalternate in position with the blades or buckets 8, the steam beingintroduced through an inlet port 6 and eX`- hausted, at the other end ofthe turbine, through an exhaust port 7.

Referring now more particularly to Fig.

2, the drum 2 is provided, at its forward end, with a piston l0, whichis shown as having the form usually adopted for balance pistons and asof less dia-meter than the main portion of the drum. It the balancepiston is of less diameter than the main portion of the drum, asindicated, the pressure of steam acting upon the said main portion willexert an end thrust which will, to a greaterl or less extent,counter-balance the thrust of the propeller. The balance piston may,however, be made of the same mean diameter as the main portion ofthedrum, and if such is the case, there will be no counter-balancing endthrust which is incident to the normal operation of the turbine. Thespace 11 in front of the piston l0 is connected with the exhaust chamberof the turbine by means of a pipe l2 in which is located a valve 13. Asthe high-pressure steam entering the inlet port G leaks, to a greater orless extent, around the piston 10 and into the space or chamber 1l, thepressure exerted in this space and against the piston depends upon theposition of the valve 13. It this valve is completely closed, the steampressure will obviously accumulate in the space l1 until it becomesapproximately equal to the pressure of the steam received at the inletport 6, and for any other position ot the valve 13, the pressure in thespace 11 will. be correspondingly reduced, so that this end pressure maybe varied in order to countcbalance the end thrust of the propellerblades. In order that this steam pressure in the space l1 may be variedautomatically in accordance with the propeller end thrust, I provide athrust bearing ld in the form of a cylinder, the inner periphery ofwhich is provided with a set of rings or collars 15 which intermesh andmake lateral engagement with corresponding rings or collars 16 on the.engine shaft 17, this thrust bearing being of such dimensions as to takea very small portion only of the thrust. Bolted to the outer end of thethrust bearing cylinder 14, is a cap 18, from which projects a stem 19having, at its outer end, a valve 20. The valve 2O is located in achamber 21 having a drain pipe outlet 22 and communicating,

by means of an opening 23, with a chamber 24, communication between thechambers 21 and 24, through the opening 23, being controlled by thevalve 20. Oil or any other Suitable fluid, under pressure obtained fromany suitable source, is introduced into 'the chamber 24 through pipes 25and 26 so connected as to provide a small orifice 27 for the lpassage ofthe fluid, this orifice in the present insta-nce being shown asadjustable by means of a needle-valve 28.

The chamber 24 is connected to the bottom of a cylinder 29 by means of'a pipe 30, an'd in the cylinder 29, is a piston 31 between which andthe upper end of the cylinder is located a coil-spring 32. The piston 31is connected, by means of a rod 33, a link 34 and a lever-,arm 35, withthe valve 13 which is'located in the pipe 12 and controls the flow ofsteam from the chamber 11 to the exhaust chamber of the engine.

The operation of the mechanism thus far described is as follows: In casethe end thrust due to the action ofthe propellers becomes greater than apredetermined amount, according to the proportioning of the apparatus,the thrust bearing will exert a greater pressure on the valve 20, thusraising the fluid-pressure in the chamber 24 and this pressure will beexerted, through the pipe 30 and the cylinder 29, against the lpiston31, which will be therefore raised against the action of the spring 32and will partially or Wholly close the valve 13, according to the degreeof end thrust, and thus cause steam pressure to accumulate in the space11 and thus exactly counter-balance the end thrust due to thepropellers. It will, of course, be generally convenient and desirable tohave the spring 32 of such strength as to maintain some definitepressure upon the thrust bearing 14 and in the chamber 24. It is to bealso understood that the degree of fluid-pressure at the orifice 27should be suflicient, when fully exerted against the piston 31, throughthe channels provided for it, to socompress they spring 32 as tocompletely close the valve 13.

The construction and arrangement of mechanism for effecting the desiredresult may be varied considerably within the scope of my invention and,while I shall not attempt to illustrate or describe all of the parts,modifications and variations of such mechanism, I have illustrated inFig. 3 a substitute for the cylinder 29 and the piston 31 which may beconveniently utilized, if. desired. i This modiiication chamber 36having a flexiblediaphragm 3.7 which is connected, by means of a rod',to a lever-ar1n-39, the free end of the latter, being connected to thelever-arm 35 for,o pergV ating the valve 13 by means of a rod- Thediaphragm 37 may be normally held-.iii its lowest position by means of acoil-spring 41 and be moved upward to effect movementy of the valve 13by fluid-pressure introduced` into the space inthe chamber 36 below thevdiaphragm through the pipe 30 fromthev chamber 24. Any other suitableform of. valves and connecting link and lever mech` anism may, ofcourse, be utilized in practice. In the case of vertical turbinesutilized for driving dynamo electric generators, the rotary members ofthe generators are generally mounted upon and supported by the rotatingmembers of the turbines which drive them and the turbine shafts aretherefore subjected to an end thrust which must be taken care of by somesuitable means. I propose to utilize my present invention for thispurpose and, in Fig. 4, have illustrated a modification which is adaptedtherefor. Since the essential parts of the mechanism which have to dowith my present invention do not differ materially from those alreadydescribed, I have given the said parts the same reference numerals asthe preceding figures and the description heretofore given may betherefore read in connection with Fig. 4, making it unnecessary torepeatsuch description Since it sometimes occurs that the steam pressureat the inlet will be but' slightly comprises v. a

higher than the exhaust pressure, as, for

counter-balance the dead weight of the rotating parts of the dynamo andturbine. In order to meet the conditions thus imposed, I may employ themodified apparatus shown in Fig. 5, which embodies an additional valvechamber 42 into which live steam is admitted through a pipe 43. TheAvalve chamber 42 is provided with a double diaphragm 44, the spacebetween which communicates with the space 11 by means of a pipe 45. theports in the double diaphragm 44, is connected, by means of a stem 47and a leverarm 48, to the stem 49 of a piston 50 which corresponds tothe piston 31 of Figs. 1, 2 and 4. The upper end of the stem 49 isprovided 1 of a link 55 and an arm 56. A cylinder 57 139' A valve 4G,which normally closes 120 and Vi ts spring 58, which correspond, respecA tively, to the cylinder 29 and spring 32 of Figs. l, 2 and t, are ofgreater longitudinal dimensions than the corresponding parts in theother figures, so that the piston 50 has a greater range of movement.It; follows, therefore, that after the said piston has moved asuiiicient distance to close the valve 13, it may still continue itsmovement, under the action of fluid-pressure, and compressI the spring53 in the cylinder and, at the same time, move the lever 48 a sufficientamount to raise the valve Lt6 and thus admit live steam, through thepipe 45, to the chamber 11 in sufficient quantity to counter-balance thedead weight of the rotating parts.

In Fig. l which shows a'general view of a turbine embodying my inventionthe steam inlet port 59 is provided with a reversing valve 60, which maybe turned, by means of any suitable device or mechanism, (not shown), todirect the steam to either the admission port6l of that end of theturbine having the blades and vaines 62 for running ahead or to theadmission port 63 for that portion of the turbine provided with theblades and vanes 64 for running astern, both the ahead and asternturbine sections having a common exhaust outlet 65. IVhen either turbineis operating under steam pressure, the other will be operating iii avacuum, and the losses due to this idle operation will be very small, asis well known to those skilled in the art.

The ahead turbine and the astern turbine might be entirely separatemachines, if desired, instead of being parts of a single. structure, ashere illustrated. lThe single shaft of the complete reversing turbine,as here shown, is provided with two thrust vbearings 66 and 67 and withtwo balance pistons 68 and 69, a chamber. 70 being provided behind thebalance piston 68 and a similar chamber 71 being` provided behind thebalance piston 69, the structure and function of these parts beingsubstantially the saine as those already described in connection withwhat is shown in the preceding figures.

When the vessel is running ahead, the thrust due to the propellers willbe exerted toward the thrust bearing 66 and,`conse quently, the bellcrank lever 72, one arm of which is connected to the thrust bearing andthe other arm of which is connected to the valve stem 7 3, will hold thevalve 20 to its seat and thus permit the Huid-pressure which is producedby a pump 7 5 and is transmitted to the cylinder 29 through the pipes 25and 30 and the chamber 24, to be exerted, in the manner alreadydescribed to close the valve 13 in the pipe l2 leading from the chamberto the exhaust port.

Vlien the steam is turned off from the is admitted to the astern turbinethrough the port 63, the thrust due to the propellers will be reversedand thus exerted toward the thrust bearing 67 in which case theapparatus at that end of the turbine, corresponding in structure andfunction to that above referred to in connection with the thrust bearing66, will operate to counterbalance the propeller thrust. At the sametime, the pressure will obviously be relieved from the thrust bearing66, andthe Huid in the corresponding chamber 24, the cylinder 29 and thepipe connecting them will ybe permitted to escape, by reason ofthelifting of the valve 20 to a greater or less degree, and will flow out,through the pipe 22, into the tank 74.

The fluid utilized in this apparatus is drawn from the tank 74 andforced, under the desired pressure, through the pipes and chambers bymeans ofv the' pump 75, which may be driven by any suitable outsidesource of power or may be driven by the turbine itself, as may bedesired.

It is, of course, apparent that there will be some lateral motion of theturbine and that the whole rotating element will move longitudinallysome small amount in going" from one thrust bearing to the other; thatis, if it is operating ahead, the position of the thrust bearing 66 willbe such as to maintain the correct adjustment of the balance piston 68.When, however, the thrust is reversed, the rotating element will movebodily lengthwise a small amount before the thrust is taken by thethrust bearing 67, and this, in turn, is so adjusted asto position thatwhen the thrust of the shaft is taken by this bearing, the balancepiston'r 69 will have the proper adjustment for the most effectivepacking.

In view of the fact that Fig. lis moie or less diagrammatic no attempthas been made to describe in detail all of the controlling devicesapplicable in connection with a reversing turbine, as it is believedthat such a description would tend to confuse rather than to elucidatethe understanding of the subject matter herein involved.

I claim as my invention:

l. In combination with an elastic fluid turbine, a piston carri-ed atone end of its rotor, a chamber behind said piston into which steampasses from the inlet end of the turbine, a passage between said chamberand the turbine exhaust port, a valve in said passage, a fluid pressureactuated device for operating said valve and means dependent upon therotor end thrust for controlling said device.

2. The combination with the stationary and rotatable members of afluid-pressure turbine and a chamber at one end of the rotatable memberinto which steam leaks from inlet port 61, by means of the valve 60, andr the turbine inlet, of a passage between said chamber and the turbineexhaust port, a valve in said passage, fluid-pressure' actuated meansfor operating said valve and a governing valve operatively connected tothe turbine shaft and serving to vary the {inidpressure utilized foroperating the firstnamed valve in accordance With the end thrustupon theturbine shaft.

3. In a steam turbine, the combination with a piston attached to andforming a part of the turbine drum and a chamber behind the piston thatis in communication with both the inlet and exhaust ports of theturbine, of a valve for controlling the exhaust passage from saidchamber, a spring for normally holding said valve open, means forapplying fluid-pressure in opposition to the spring to close the valveand a valve operatively connected to the turbine shaft to govern theapplication of said fluid-pressure in accordance with the end thrustupon the shaft.

4. The combination with the stationary and rotatable members of a steamturbine and a chamber at one end of the rotatable member into whichsteam is admitted from the inlet port, of a passage from said chamber tothe exhaust port, a valve in said passage, a spring tending to normallyopen said valve, a. piston against which said spring acts, means forapplying fluid-pressure to said piston in opposition to the spring and agoverning valve operatively connected to the turbine shaft and servingto regulate said fluid-pressure in accordance With the end thrust uponthe shaft.

5. In a turbine, a rotor, a plurality of bearings therefor, a balancingchamber near each bearing, a piston in each balancing chamber and meansfor connecting each balancing chamber with the exhaust pas sages of saidturbine.

G. In a turbine, a rotor, a plurality of bearings therefor, and apressure balance piston near each bearing.

7. In a turbine, a rotor, a plurality of bearings therefor, a balancingchamber near each bearing, a piston Within each chamber and means,dependent on the longitudinal thrust on the rotor, for Varying thebalancing effect of one or the'other of said pistons.

8. yIn a turbine, the combination of a rotor,

a casing therefor, a balancing chamber at each end of said casing andmeans, controlled by the longitudinal motion incident to unbalanced endthrust on said rotor, for varying the pressure in one or the other ofsaid chambers for the purpose of balancing said rotor.

9. In combination with an elastic fluid turbine, a piston carried at oneend of the rotor element of said turbine, a chamber provided behind saidpiston Within the cas ing of the turbine and into which steam passesfrom the inlet end of the turbine, a passage between said chamber andthe turbine exhaust, a valve located Within said passage, a fluidactuated mechanism controlling the operation of said valve and a relaydevice actuated by the turbine rotor and dependent upon the rotor endthrust for controlling the operation of said valve oper-V atingmechanism.

10. In combination with the rotor and stator elements of an elasticfiuid turbine, a piston carried by the rotor element of the turbine, achamber provided behind said piston and Within said stator, a passagelocatedv between said chamber and the exhaust of the turbine, a valvecontrolling the delivery of fluid through said passage, a fluid actuatedmechanism for said valve and a relay device actuated vby thelongitudinal motion of the rotor for controlling the oper ation of saidvalve actuating mechanism.

11. In combination in a turbine, a rotor element, a stator elementsurrounding said rotor,a piston carried at one end of the rotor, achamber located behind said piston and Within said casing, a passagebetween said chamber and the exhaust of the turbine, a valvecontrolling` the delivery of iiuid through said passage, a fluidactuated mech-` anism for controllinff the operation of said valve, andavrelay cevice actuated by the longitudinal motion of the turbine forcontrolling the delivery of fluid to said fluid actuated mechanism.

In testimony whereof, I have hereunto subscribed my name this 28th dayof December, 1903.

FRANCIS HODGKINSON. Witnesses:

WV. S. THOMPSON, J. A. MACMURCHY.

